Unraveling the Fe₃O₄ NPs role in self-assembled magnetic zinc oxide nanorods for methylene blue photodegradation

Nowadays, water pollution represents one of the most concerning environmental issues that affect society. Worldwide, around 80% of wastewater is discharged into the environment without receiving proper treatment, according to the United Nations. The recent breakthroughs in nanotechnology have encouraged the development and use of nanomaterials for the water remediation process. The present work proposes the preparation of a magnetic zinc oxide nanophotocatalyst (ZnO-Fe₃O₄-50). The nanomaterials were characterized by various techniques such as TEM, SEM, FTIR-ATR, XRD, XPS, UV–vis, magnetic and electrochemical determinations. The photodegradation and photo-Fenton efficiencies of the prepared materials were evaluated using methylene blue (MB) as a test dye molecule. The most likely photodegradation mechanism for ZnO-Fe₃O₄-50 hybrid material and the role of magnetite nanoparticles as promoters of ROS formation were elucidated. The photodegradation efficiency (η) for MB was 97% after 45 min of UV-light irradiation, while in the presence of H₂O₂, the sameη value was achieved after 20 min of irradiation.